Single use syringe

ABSTRACT

A single use syringe .[.having.]. .Iadd.has .Iaddend.an interacting piston and cylinder which cooperate to define a variable volume working space.[.,.]..Iadd.; .Iaddend.the syringe includes a valve body located in the chamber so as to divide the chamber into a first and second sub-chamber, .Iadd.and .Iaddend.the valve body has valves which permit a liquid to be initially drawn into the syringe and then injected, but prevent a subsequent liquid being drawn into the syringe. .Iadd.A valve for the syringe is also claimed. .Iaddend.

.Iadd.This is a continuation (reissue) of U.S. Pat. No. 4,941,879 (Jul.17, 1990) from U.S. application Ser. No. 07/373,291 filed Jun. 14, 1989from PCT No. PCT/AU88/00402 filed Oct. 14, 1988. .Iaddend.

.Iadd.FIELD .Iaddend.

The invention relates to hypodermic syringes .Iadd.and valves,.Iaddend.and in particular to a single use hypodermic syringe .Iadd.andsyringe valve. .Iaddend.

.Iadd.BACKGROUND .Iaddend.

Disposable syringes for which a single use is contemplated are wellknown as.Iadd., .Iaddend.for example.Iadd., .Iaddend.syringes for theinjection of insulin in diabetics. Nothing, however, prevents theresyringes from being reused (.Iadd.re-used) .Iaddend.in a necessarilyunsterile state. The result .Iadd.is .Iaddend.that .[.contamination.].syringes.Iadd., .Iaddend.when used .Iadd.contaminated,.Iaddend.contribute to the spreading of disease such as AIDS orhepatitis.

Accordingly.Iadd., it .Iaddend.is desirable for syringes to be designedfor a single use only.Iadd., .Iaddend.to inhibit their re-use andtherefore the risk of using contaminated syringes.

Previously known single use syringes usually incorporate a modificationof the piston of the syringe so that it is jammed in its fully insertedposition adjacent the needle. These previously known devices have thedisadvantage that the piston can become inadvertently jammed prior to aliquid being drawn into the cylinder of the syringe.

Described in British Patent No. 1,550,310 and French Patent No.2,348,708 is a single use syringe. The syringe has a detachable pistonwhich prevents re-use of the syringe. Once the piston has been moved tothe minimum volume position, movement of the piston to again draw in aliquid is prohibited since the piston rod becomes detached from thepiston head. This syringe suffers from the disadvantage that the pistoncan become detached from the piston rod.Iadd., .Iaddend.and the syringecannot be operated to test whether the syringe has been correctlyinserted. This is usually achieved by pulling back on the piston rod todraw into the syringe a small portion of blood. A similar syringe isdisclosed in British Patent No. 2,015,883.Iadd.; .Iaddend.again.Iadd.,.Iaddend.this particular device shows a detachable piston which suffersfrom the disadvantages as discussed.

French Patent No. 2,298,340 discloses a single use syringe, with thepiston being provided with a frangible diaphragm. Once the piston hasbeen moved to the minimum volume position, a bar penetrates thediaphragm.Iadd., .Iaddend.preventing re-use of the syringe..Iadd.Disclosed in .Iaddend.British Patent No. 1,454,540 is .Iadd.asyringe .Iaddend.of a similar construction, in that the piston isprovided with a means of damaging the body of the syringe.Iadd.,.Iaddend.preventing its re-use. Both .[.the.]. .Iadd.of these.Iaddend.syringes suffer from the disadvantage that they do not enableoperation of the syringe to test whether the needle has .[.be.]..Iadd.been .Iaddend.correctly located.

U.S. Pat. No. 3,951,146 discloses a single use syringe which employs aratchet mechanism to prevent withdrawal of the piston. Again.Iadd.,.Iaddend.this particular type of syringe does not enable testing todetermine whether the needle has been correctly located.Iadd.. Thesyringe of .Iaddend.British Patent No. 2,184,657 also uses a pawl toengage behind the piston to prevent re-use. It has the samedisadvantages. .Iadd.Syringes of .Iaddend.U.S. Pat. Nos. 3,478,937 and3,890,971 also employ pawls or detent members which prevent rewardmovement of the piston. They suffer similar disadvantages.

U.S. Pat. No. 4,233,975 discloses a single use syringe with a plungermember which engages within a socket when the piston is moved to theminimum volume position. The plunger cannot be retracted.Iadd.,.Iaddend.and .Iadd.this .Iaddend.prevents re-use of the syringe.

U.S. Pat. No. 4,650,468 is similar to several of the above discussedpatents since .[.it uses.]. .Iadd.its syringe has .Iaddend.a plunger orpiston which is automatically locked in a position preventing re-use.

The above discussed previously known single use syringes suffer from thefurther disadvantage in that they require the piston to be moved to theminimum volume .[.of.]. position before any action is taken to renderthe syringe inoperative.

.Iadd.U.S. Pat. Nos. 4,643,723 and 4,781,683 may be of interest also.Note too, French Patent No. 2,632,190.

.Iadd.OBJECT .Iaddend.

It is the object of the present invention to overcome or substantiallyameliorate the above disadvantages.

.Iadd.INVENTION DISCLOSURE .Iaddend.

There is disclosed herein a single use syringe comprising:

an inter-acting piston and cylinder defining a variable volume chamberwithin which a liquid to be injected is drawn;

a needle mounting at one end of said cylinder, to receive a needle, apassage extending through said mounting enabling liquid communicationbetween said cylinder and said needle;

a piston rod attached to said piston and operable by a user to causemovement of said piston to vary the volume of said chamber;

a valve means including a valve body located within said chamber betweensaid mounting and said piston and dividing said chamber into a firstsub-chamber located between said mounting and valve means, and a secondsub-chamber located between said valve means and said piston, said valvebody being movable longitudinally of said cylinder between a firstposition and a second position, and said valve means includes a firstvalve which, when said body is in said first position, permits flow fromsaid first sub-chamber to said second sub-chamber and prevents flow fromsaid second sub-chamber to said first sub-chamber, but when said body isin said second position, said first valve permits flow from said secondsub-chamber to said first sub-chamber and prevents flow from said firstsub-chamber to said second sub-chamber, and a second valve which, whensaid body is in said first position, permits flow from said firstsub-chamber to said second sub-chamber, but prevents flow from saidfirst sub-chamber to said second sub-chamber when said body is in saidsecond position; and

means to prevent movement of said body from said second position to saidfirst position.

There is further disclosed herein a valve assembly for a syringe havingan interacting piston and cylinder, with the cylinder terminating at oneend with a mounting to receive a syringe needle, said piston andcylinder co-operating to define a variable volume working chamber whichreceives a liquid to be injected by the syringe, said valve assemblybeing adapted to be located within said chamber so as to divide saidchamber into a first sub-chamber located adjacent the needle mounting,and a second sub-chamber located adjacent the piston, said valveassembly including a valve sleeve to be sealingly received within saidcylinder so as to be coaxial with respect thereto, said sleeve having aninternal peripheral surface;

a movable valve member received within said sleeve and sealinglyco-operating therewith so that in use of the syringe the valve memberselectively controls the direction of flow of liquid within the syringe,said valve member having a pair of axially spaced annular sealingsurfaces which sealingly engage said sleeve, and which are resilientlydeformable;

a first set of sleeve projections extending inwardly of said sleeve toengage a first one of said sealing surfaces;

a second set of sleeve projections extending inwardly of said sleeve toengage the other sealing surface, said second set of sleeve projectionsbeing spaced longitudinally of said first set of sleeve projections; and

wherein said valve member is longitudinally movable between a first.[.portion.]. .Iadd.position .Iaddend.wherein the first annular sealingsurface is engaged with the first set of sleeve projections so as to bedeformed and deflected from said sleeve so that liquid may pass thereby,and the other sealing surface is in sealing contact with said sleeve andinhibits the direction of fluid flow in a first direction, and a secondposition wherein said second sealing surface is engaged with said secondset of sleeve projections so that liquid may pass thereby, and saidfirst sealing surface is sealingly engaged with said sleeve to inhibitfluid flow in a second direction, which is opposite to said firstdirection.

.Iadd.FURTHER DISCLOSURE .Iaddend.

A preferred form of the present invention will now be described by wayof example with reference to accompanying drawings, wherein:

FIG. 1 is a schematic perspective part section view of a single usesyringe;

FIG. 2 is a schematic section side elevation of a portion of the syringeof FIG. 1 in a first operative mode;

FIG. 3 is a schematic sectioned side elevation of the syringe portion ofFIG. 2;

FIG. 4 is a schematic sectioned side elevation of the syringe portion ofFIG. 2 in a second operative position;

FIG. 5 is a schematic side elevation of an alternative syringe to thatshown in FIG. 1;

FIG. 6 is a schematic part sectioned perspective view of a single usesyringe;

FIG. 7 is a schematic sectioned side elevation of a portion of thesyringe of FIG. 6, with the syringe in a first mode of operation;

FIG. 8 is a schematic sectioned side elevation of the portion of FIG.7.Iadd., .Iaddend.with the syringe in a second mode of operation;

FIG. 9 is a schematic sectioned side elevation of the portion of FIG. 7sectioned along the line 9--9;

FIG. 10 is a schematic sectioned side elevation of a portion of asyringe;

FIG. 11 is a schematic end elevation of the portion of FIG. 10;

FIG. 12 is a schematic side elevation of a further syringe portion;

FIG. 13 is a schematic end elevation of the portion of FIG. 12;

FIG. 14 is a schematic part sectioned side elevation of a valve assemblyof a single use syringe, with the valve member thereof in a firstoperative position;

FIG. 15 is a schematic part sectioned side elevation of the valveassembly of FIG. 14, with the valve member in a second operativeposition;

FIG. 16 is a schematic part sectioned side elevation of the valveassembly of FIG. 14, with the valve member in a third operativeposition, and

FIG. 17 is a schematic part sectioned end elevation of the valveassembly of FIG. 14 sectioned along the line 17--17.

In the preferred embodiment of the invention shown in the FIGS. 1 to 5,the valve has been incorporated in the needle portion 3 of a syringe,the syringe main body portion 1 and needle portion 3 being madepreferably as separate pieces. The valve includes a sliding portion 10comprising a cylindrical body 14, at the opposite ends of whichperipheral seals 34 and 36 are provided. Flexible flaps 17 and 19 extendfrom opposite ends and at diametrically opposed sections from arms 15and 16 of cylindrical body 14. In co-operation with the wall 13 of thesyringe.Iadd., .Iaddend.flap 19 acts as an inlet valve while the flap 17acts as an outlet valve in a manner to be described below.

The wall 13 includes two outwardly extending portions 8 and 9. Portion 8has a sloping portion extending from point 24 to point 32 to providechannel 18. The portion 9 has a sloping portion from point 22 to point23 to provide channel 21. The wall 13 is also provided with a portion 28extending towards the needle 4 from point 22, ending in a shoulder 25which forms a stop for the body 14 in a manner to be explained below.

The flaps 17 and 19 are made of such a resilient material that in theirresting state as shown in FIG. 2 they lie against the wall 13. The flaps17 and 19 as shown in FIGS. 1..]..Iadd., .Iaddend.2 and 4 are shaped soas to provide a sealing action not only against wall 13 within channels18 and 21 but also against the side walls of these channels.

At approximately right angles to the flaps 17 and .[.19a.]. .Iadd.19, a.Iaddend.pair of fingers 30 and 31 is provided as best shown in FIG. 3.These fingers extend from the body 14 near seal means 36 and at the endof sliding portion 10 distal of the needle tip 4. Fingers 30 and 31extend into channels 50 and 51, which are interrupted by inclinedsurfaces 53 and 55 which lead to forwardly facing shoulders 45. Thefingers 30 and 31 are suitably resilient to enable them to bend uponmotion of the sliding portion 10 in the forward direction of arrow 42 sothat upon passing the shoulder 45 they re-enter the channels 50 and 51and thereby prevent return movement of the valve body 10. In addition,the fingers 30 and 31 help to centre (center) the body 10 within thewall 13, for example, by seating against the inclined surfaces 53 and.Iadd.55 .Iaddend.in their initial state.

The operation of the valve will now be described with particularreference to FIGS 2, 3 and 4. The drawing of fluid into the needle 4 inthe direction of arrow 40 will cause the flap 19 to move away from thewall in the channel 21, allowing fluid past the cylindrical body 14 viachannel 21. The flap 19 will remain open as long as the .[.filing.]..Iadd.filling .Iaddend.stroke continues.

Once the desired dose has been drawn up.Iadd., .Iaddend.the plunger 2 ismoved in the direction of arrow 42. This initiates an expulsion stroke.The pressure of fluid being forced in the direction of arrow 42 by theplunger 2 in the main body portion 1 of the syringe causes the flap 19to seat against the surface of the fixed portion 13. The cylindricalpart 14 is driven in the direction of arrow 42 by fluid pressure. Thisforces the seal 34 of the body 14 against point 22 to completely closechannel 21 while dragging flap 14 therealong. Further motion in thedirection of arrow 42 can continue until the body 14 presses against.[.should.]. .Iadd.shoulder .Iaddend.25 thereby (FIG. 4).

Once the seal 36 of the cylindrical part 14 has cleared the point32.Iadd., .Iaddend.fluid pressure will open the flap 17 to allowexpulsion of fluid through the needle top portion 4. Concurrently.Iadd.,.Iaddend.the fingers 30 and 31 become engaged forward of the shoulders45. The expulsion stroke of the syringe is completed as desired.

Refilling of the syringe is now prevented. Flap .Iadd.17 .Iaddend.willallow expulsion of the contents of a syringe.Iadd., .Iaddend.but uponinitiation of a stroke in the direction of arrow 40 and flap 17 willengage the wall 13.Iadd., .Iaddend.preventing the filling of thesyringe, while the body 14 moves slightly in the direction of arrow 40until engagement of the fingers 30 and 31 with the shoulders 45 preventsfurther movement of the body 14. The body 14 is then located with theseal 36 in contact with the wall 13 at point 32 so that the flow offluid in the direction of arrow 40 is prevented. This effectively limitsthe syringe having these valve means to being used for .Iadd.a.Iaddend.single filling and expulsion stroke.

The material used for the body 14, the flaps 17.[.,.]. .Iadd.and.Iaddend.19.Iadd., .Iaddend.and the fingers 30 and 31 may be anysuitably resilient and pharmacologically acceptable material such as.[.non-prene.]. .Iadd.neoprene.Iaddend..

Though the preferred embodiment shows the invention in the needleportion of a syringe.Iadd., .Iaddend.other ways of carrying out theinvention are also contemplated. For example, the valve means of theinvention can be provided in the neck portion 5, the end portion of themain body portion 1, or in a needle portion 3 integral with the mainbody of a syringe. The valve means can also be provided as a separatemodule in any of the portions 3, 5 or 6, or as a module which issecurely fixed at manufacture intermediate the neck portion 5 and theneedle portion 3 of a syringe, as illustrated in FIG. 5. The main bodyportion 1, the valve means 7.Iadd., .Iaddend.and the needle portion3.Iadd., .Iaddend.in the latter .[.thereby forming.]. .Iadd.case, form.Iaddend.a single integral unit. Equally.Iadd., .Iaddend.the valve means7 can be fixed to the neck portion 5, or .Iadd.to .Iaddend.the needleportion 3.Iadd., .Iaddend.separately.Iadd., .Iaddend.for cooperationwith a needle portion 3 or a neck portion 5.Iadd.,.Iaddend.respectively.Iadd., .Iaddend.of a syringe.

When the valve means is used as a separate module within region 6 of themain body portion 1 of a syringe, it is to be understood that the modulecan be inserted as a plug, the size of which can be .[.standardised.].(.Iadd.standardized) .Iaddend.and fitted to variously sized syringes bysleeves or other suitable fixing or securing means.

In any of the above situations there is a .[.possibilitly.]..Iadd.possibility .Iaddend.that the syringe may be re-usable if theplunger portion 2 is withdrawn and the syringe filled from the rear. Toprevent this situation the rear end of the main body portion 1 throughwhich the plunger is inserted can be crimped or heat staked after theplunger has been inserted at manufacture.

Equally, stop means can be provided to prevent false operation of thevalve means during transit.

In FIGS. 6 to 9 of the accompanying drawings there is schematicallydepicted a syringe 110 comprising an interacting cylinder 111 and piston112 which co-operate to define a sealed chamber 113. The leading portionof the cylinder 12 is closed by a needle mounting 114 which receives asyringe needle 115.

Extending rearwardly from the piston 112 is a piston rod 116 extendingto an end flange 117. The end of the cylinder 111 is provided with apair of flanges 118 which are gripped by the user together with theflange 117. The piston 112 is provided with one or more sealing rings119.

Located within the chamber 113 is a movable valve member 120 which isslidably received by the internal cylindrical surface of the cylinder111, and .Iadd.which .Iaddend.divides the chamber 113 into twosub-chambers 121 and 122. The sub-chamber 121 .[.being.]. .Iadd.is.Iaddend.located adjacent the needle mounting 114.[.,.]. while thesub-chamber 122 is located between the piston 112 and the valve assembly120.

The valve member 120 includes a main body 123 upon which there ismounted a pair of valve flaps 124 and 125 as well as a pair of pawlmembers 126.

The internal peripheral surface of the cylinder 111 is provided withshaped recesses 127 which slidably receive the valve flaps 125, andshaped recesses 128 which receive the pawl members 126.

The internal peripheral surface of the cylinder 111 is also providedwith abutments 129 which are positioned to be engaged by the pawlmembers 126.

The valve member 120 is longitudinally slidably movable within thecylinder 111 so as to be movable between a first operative position asshown in FIG. .[.2.]. .Iadd.7.Iaddend., and a second operative positionas shown in FIG. .[.3.]. .Iadd.8. .Iaddend.In the operative position ofFIG. .[.2.]. .Iadd.7.Iaddend., a user of the syringe can increase thevolume of the chamber 113 by moving the piston away from the needle.[.113.]. .Iadd.115.Iaddend.. A liquid is then drawn in through theneedle .Iadd.115 .Iaddend.into the chamber 113 and is allowed to passbetween the sub-chambers 121 and 122 via inward deflection of the valveflap 125. The valve flap 125 deflects towards the longitudinal axis.[.30.]. .Iadd.130 .Iaddend.of the cylinder 111. Once a desired amountof liquid has been drawn into the syringe 110, the needle 115 isinserted.Iadd., .Iaddend.and the piston 112 .Iadd.is .Iaddend.movedtowards the needle 115. As the pressure of in the .[.chamber.]..Iadd.sub-chamber .Iaddend.122 increases, the valve flap 125 is forcedinto sealing engagement with the internal peripheral surface of thecylinder 111. This pressure further causes movement of the valve member120 towards the needle 115 until the body 123 abuts a step 131, as shownin FIG. .[.3.]. .Iadd.8.Iaddend.. Further movement of the piston 112then causes the liquid to move past the body 123 to cause inwarddeflection of the valve flap 124 towards the longitudinal axis 130.

In the position shown in FIG. .[.3.]. .Iadd.8, .Iaddend.it should beappreciated that the body 123 is in sealing engagement with the internalperipheral surface of the cylinder 111 apart from the recess 127 whichis selectively closed by the valve flap 124.

When the valve assembly 120 is in the position shown by FIG. .[.3.]..Iadd.8.Iaddend., the pawl members 126 are located forward of theabutments 129. Accordingly, if an attempt is made to re-use the syringeby again moving the piston 112 away from the needle 115, the valvemember will not return to the position as shown in FIG. .[.2.]..Iadd.7.Iaddend.. However, while in the position of FIG. .[.3.]..Iadd.8.Iaddend., the valve flap 124 prohibits liquid being drawn intothe chamber 113, and .[.therefor.]. .Iadd.therefore, .Iaddend.thesub-chamber 122 is sealingly cut off from the sub-chamber 121.

It is desirable in some instances to ensure (.Iadd.insure) .Iaddend.thatthe needle .[.25.]. .Iadd.115 .Iaddend.has been correctly located bydrawing into the syringe 110 a small amount of blood. This is done afterthe syringe .Iadd.110 .Iaddend.has been filled with a liquid to beinjected. To provide for this, the step 131 is located relative to theabutments 129 such that a small movement of the valve member 120 awayfrom the needle 115 is possible until the pawl members .[.26.]..Iadd.126 .Iaddend.engage the abutments 129.

In FIGS. .[.210.]. .Iadd.10 .Iaddend.and .[.211.]. .Iadd.11 .Iaddend.ofthe accompanying drawings, there is schematically depicted a portion 210of a syringe. The syringe includes a cylindrical wall .[.111.]..Iadd.211 .Iaddend.which sealingly slidably receives a piston .[.whichis not.]..Iadd.(not .Iaddend.illustrated(.Iadd.unillustrated)).Iaddend.. One end of the chamber 212 is closed bythe piston.[.,.]. while the other end of the chamber 212 is closed bythe piston.[.,.]. while the other end of the chamber 212 is closed by aneedle mounting (.Iadd.unillustrated). .Iaddend.The chamber 212 isdivided into two sub-chambers 213 and 214 by means of a valve member215. The valve member 215 is formed of flexible resilient material andis provided with a first flexible end wall 216, and .Iadd.with.Iaddend.a second end wall 217.

The cylindrical wall 211 has an internal peripheral surface providedwith an annular lip 218 and at least one longitudinally extendingprojection 219. The projections 219 extend longitudinally from this lip218 towards the piston.

Located forward from the lip 218.Iadd., .Iaddend.towards the needlemounting, is at least one projection 220.

In operation of the syringe described with reference to FIGS. .[.1.]..Iadd.10 .Iaddend.and .[.2.]. .Iadd.11, .Iaddend.initially the valvemember 215 is located engaged by the projections 219 so that the endwall 217 is at least partly deformed, as best seen in FIG. .[.2.]..Iadd.11.Iaddend.. The piston is also located so that the chamber 212has a minimum volume. Thereafter, a liquid to be injected is drawn intothe syringe by the piston being moved away from the valve member 215 inthe direction of the arrow 221. Once the desired amount of liquid iscontained within the syringe, the needle is oriented vertically.Iadd.,.Iaddend.and air .Iadd.is .Iaddend.expelled from within the syringe. Itshould be appreciated that the vast majority of the liquid to beinjected is located ion the sub-chamber 214. The liquid is allowed toenter the sub-chamber 214 by passing around the deformed end wall 217and causing deflection of the end wall 216.

Once the desired amount of liquid is located in the syringe, the needleis oriented vertically.Iadd., .Iaddend.and air .Iadd.is.Iaddend.expelled from within the syringe. This operation will move thevalve member 215 to a position located closer to the needle mounting.More particularly, the end wall 217 is moved from engagement with theprojections 219, and abuts the projections 220. When in this position,the end wall 216 is engaged by the projections 219. It should beappreciated that this forward movement of the valve member 215 is causedby the pressure within the liquid, applied against the end wall 216.

Further use of the syringe, by movement of the piston again in thedirection of the arrow 221 is prevented by the valve member 215 beingmoved in the direction of the arrow 221 until the valve member .Iadd.215.Iaddend.sealingly engages the annular lip 218. Since insufficient forceand be applied to the valve member 215 to cause deformation thereof byengagement with the projections 219, further use of the syringe isinhibited.

It should be appreciated that the projections 220 ar e spaced from theprojections 219 so that a certain amount of movement of the valve member215 is permitted until the end wall 217 sealingly contacts the lip 218.This enables the syringe needle to be inserted in a vein and the pistondrawn back, a limited amount, to draw in a small quantity of blood tothereby detect whether the syringe needle has been correctly inserted.

In FIGS. .[.3.]. .Iadd.12 .Iaddend.and .[.4.]. .Iadd.13 .Iaddend.thereis schematically depicted a portion 230 of a syringe. In this particularembodiment, the syringe has a cylindrical wall 231 encompassing achamber 232. The chamber is closed at one end by means of apiston.[.,.]. (.Iadd.unillustrated) .Iaddend.while the other end isclosed by a needle mounting (.Iadd.unillustrated).Iaddend..

The chamber 232 is divided into two sub-chambers 233 and 234 by means ofa valve member 235. The valve member 235 is formed of flexible resilientmaterial and has a pair of end walls 236 and 237. The end walls 236 and237 are joined by a stem 238.

The internal peripheral surface of the wall 231 is provided with anannular lip 239 as well as at least one longitudinally extendingprojection 240.

In the position depicted in FIGS. 12 and 13, the end wall .[.217.]..Iadd.237 .Iaddend.is engaging the projections 240 so as to be deformedthereby.

Initially, the valve member 235 is located in the position depicted inFIG. .[.3.]. .Iadd.12.Iaddend.. The piston is located so that the volumeof the chamber 232 is minimized. To draw a liquid into the syringe, thepiston is moved in the direction of the arrow 241 away from the valvemember 235. The liquid is drawn into the sub-chamber 234 via movement ofthe liquid past the end wall 237, due to its deformation, and .Iadd.to.Iaddend.the deflection of the end wall 236 away from the cylindricalwall 231. Once the desired amount of liquid has been drawn into thesyringe, the needle is oriented vertically and air .Iadd.is.Iaddend.expelled. Movement of the piston to achieve this.[.,.]. movesthe valve member 235 to a position such that the end wall 237 is forwardof the projections 240. However, the end wall 236 is engaged by theprojections 240 and is deformed to enable liquid .[.tc.]. .Iadd.to.Iaddend.pass thereby and between the end wall 237 and the internalperipheral surface of the cylindrical wall 231.

Once the needle has been inserted, the piston is moved so as to mimimizethe volume of the chamber 232 with the liquid again passing by thedeformed end wall 236 and past the end wall 237.

Re-use of the syringe is inhibited since movement of the piston again inthe direction 241 moves the valve member 235 to bring the end wall 237back into sealing contact with the annular lip 239.

The valve member 235 is permitted a certain degree of movement beforethe end wall 237 is moved back into sealing contact with the annular lip239, to enable the syringe to be inserted and a smaller amount of blooddrawn into the syringe to indicate whether the needle has been correctlylocated.

In FIGS. 14 to 17 of the accompanying drawings there is schismaticallydepicted a valve assembly 310 to be mounted within the end portion 311of a syringe. The end portion 311 includes a needle mounting 312 toreceive a syringe needle 313. The end portion 311 includes a generallycylindrical section 314, which if need be may be slightly tapered so asto be "frustoconical" in configuration. Extending from the cylindricalportion 314 is the main body 315 of the syringe which slidably sealinglyreceives the piston (not illustrated).

The cylindrical section 314 receives the valve assembly 310. The valveassembly 310 includes a valve sleeve 316 which has an outer peripheralsurface sealingly mated with the internal peripheral surface of thecylindrical section 314. The internal peripheral surface 317 slidablyreceives a movable valve member 318. The valve member 318 is of aunitary construction, and .Iadd.it .Iaddend.is preferably moulded(.Iadd.molded) .Iaddend.or formed from a resilient elastic material. Thevalve member 318 has a pair of annular sealing flanges 319 and 320 whichprovide sealing surfaces which slidably engage the surface 317.

The surface 317 is provided with two sets of projections 321 and 322,with the set of projections 321 being located closer to the needle thanthe second set of projections 322. The first set of projections 321.[.include.]. .Iadd.includes .Iaddend.two projections which are locatedon diametrically opposite sides of the surface 317, and .Iadd.which.Iaddend.are coextensive and parallel. The second set of projections 322.[.which are.]..Iadd., .Iaddend. longitudinally spaced from the firstset of projections 321 toward the rear of the syringe, also.[.include.]. .Iadd.includes .Iaddend.a pair of projections, which arelocated on diametrically opposite sided of the surface 317, and.Iadd.which .Iaddend.are coextensive and parallel. The projections 322are spaced .[.390.]. .Iadd.at 90 .Iaddend.degrees angularly about thelongitudinal axis 331, from the projections 321.

As best seen in FIGS. .[.1.]. .Iadd.14 .Iaddend.and .[.3.]..Iadd.16.Iaddend., each of the projections 321 and 322 has a leadingface 323 which may be generally normal to the surface 317, or.Iadd.which may be .Iaddend.slightly inclined thereto so as to provide abarb which will engage the movable valve member 318. The rear end ofeach projection .Iadd.set .Iaddend.321 and 322 is provided by a rampsurface 324.

The valve member 318 is provided with an annular recess 325 with aleading surface 326. The recess 325 has a rear surface 327. The surface326 extends generally normal to the longitudinal axis 331.[.,.]. whilethe surface 327 is inclined to the axis 331 by an acute angle.

Each of the projections 321 is provided with a longitudinally extendingpassage 328 through which a liquid to be injected may pass.

In operation of the above described valve assembly 310, the movablevalve member 318 begins in a starting position as seen in .[.FIGS. 1 and4.]. .Iadd.FIG. 14.Iaddend.. The projections 321 are engaged with theflange 319 so that the flange 319 is resiliently deformed so thatportions thereof are spaced from the surface 317 so that the flange 319is no longer in sealing contact with the surface 317. When the piston ofthe syringe is located adjacent the valve assembly 310 and moved in thedirection of the arrow 330, a liquid is drawn in through the needle 313,.[.pass.]. .Iadd.past .Iaddend.the flange 319, and.Iadd., .Iaddend.dueto the pressure differential across the flange 320, the flange 320deflects from a sealing contact with the surface 317, .[.and.]..Iadd.which .Iaddend.permits the liquid to enter the main chamber 332 ofthe syringe. When the desired amount or liquid has been drawn into thesyringe, and the operator wishes to expel any air contained in thesyringe.Iadd., .Iaddend.the needle 313 is placed so as to extendvertically. Thereafter, any air contained in the syringe will moveupwardly. The operator then moves the piston or plunger to expel theair. When the piston moves, the pressure .[.within.]. .Iadd.of.Iaddend.the liquid within the chamber 331 causes the valve member 318to move towards the needle 313.[.,.]. so that the flange 319 moves fromoperative contact with the projections .[.321.]. .Iadd.322.Iaddend..When this occurs, the flange 320 moves in contact with the projections.[.322.]. .Iadd.321.Iaddend.. Accordingly, the flange .[.320.]..Iadd.319 .Iaddend.is moved from sealing contact with the surface317.Iadd.. .Iaddend.The liquid then is able to pass the flange 320 andcause deflection of the flange 320 to pass towards the needle 313. Thisposition is shown in FIG. .[.2.]. .Iadd.15.Iaddend..

In some instances it is desirable to test to determine whether theneedle has been correctly inserted.Iadd.. .Iaddend.This is achieved bydrawing back on the piston and drawing into the syringe a small amountof blood. This test can be carried out due to the distance between thesurface 326 and the surface 323, which distance.[.,.]. permits a smallamount of rearward movement of valve member 318. When the piston isdrawn back, the movable valve member 318 moves until the surface 326engages the surfaces 323 of the projections 321. Once this has occurred,the movable valve member 318 is prevented from any further rearwardmovement. Once in this position, the flanges 319 are in sealing contactwith the surface 317 and prevent any further material being drawn intothe syringe. To inject the liquid contained within the chamber 332,again the piston is moved forward towards the needle 313 .[.and past theflanges 320 (as they are deformed by the projections 322).].. Thepressure .[.in.]. .Iadd.of .Iaddend.the liquid then deflects the flanges319 away from the surface 317 so that the liquid can then reach the.[.needles.]. .Iadd.needle .Iaddend.313.

Re-use of the syringe is inhibited since once the syringe has been used,the surface 326 is located forward of the surfaces 323 of theprojections 321. Once this has occurred, the valve member 318 preventsany liquid being drawn into the chamber 332.

We claim:
 1. A single use syringe comprising:an inter-acting piston andcylinder defining a variable chamber within which a liquid to beinjected is drawn; a needle mounting at one end of said cylinder, toreceive a needle, a passage extending through said mounting enablingliquid communication between said .[.cylinder.]. .Iadd.chamber.Iaddend.and said needle; a piston rod attached to said piston andoperable by a user to cause movement of said piston to vary the volumeof said chamber; a valve means including a valve body located withinsaid chamber between said mounting and said piston and dividing saidchamber into a first sub-chamber located between said mounting and valvemeans.[.,.]. and a second sub-chamber located between said valve meansand said piston, said valve body being movable longitudinally of saidcylinder between a first position and a second position, .[.and.]..Iadd.wherein .Iaddend.said valve means includes .Iadd.1) .Iaddend.afirst valve which, when said .Iadd.valve .Iaddend.body is in said firstposition, permits flow from said first sub-chamber to said secondsub-chamber and prevents flow from said second sub-chamber to said firstsub-chamber, but when said .Iadd.valve .Iaddend.body is in said secondposition, said first valve permits flow form said second sub-chamber tosaid first sub-chamber .[.and prevents flow from said first sub-chamberto said second sub-chamber,.]..Iadd., .Iaddend. and .Iadd.2) .Iaddend.asecond valve which, when said .Iadd.valve .Iaddend.body is in said firstposition, permits flow from said first sub-chamber to said secondsub-chamber, but prevents flow from said first sub-chamber to saidsecond sub-chamber when said .Iadd.valve .Iaddend.body is in said secondposition.[.;.]..Iadd., .Iaddend.and means to prevent movement of said.Iadd.valve .Iaddend.body from said second position to said firstposition.
 2. The syringe of claim 1, wherein said .[.first.]..Iadd.second .Iaddend.position of said .Iadd.valve .Iaddend.body iscloser to said mounting than .[.the second.]. .Iadd.said first.Iaddend.position of said .Iadd.valve .Iaddend.body.
 3. The syringe ofclaim 1 or 2.Iadd., .Iaddend.wherein said first and second valvesinclude valve flaps attached to said .Iadd.valve .Iaddend.body, and saidcylinder has recesses selectively sealingly cooperating with said valveflaps.
 4. The syringe of claim .[.2,.]. .Iadd.3 .Iaddend.furtherincluding first projection means to engage the valve flap of said firstvalve, which first projection means is positioned to deflect said valveflap from sealing engagement with said cylinder when said .Iadd.valve.Iaddend.body is in said second position, and second projection means toengage .[.thje.]. .Iadd.the .Iaddend.valve flap of said second valvemeans to move it from sealing contact with said cylinder when said.Iadd.valve .Iaddend.body is in said first position.
 5. The syringe ofclaim 1 .Iadd.or 2, .Iaddend.wherein said valve body is formed ofresilient material, and said valves include resilient .[.annular.].flanges on said .Iadd.valve .Iaddend.body, and a first projection meanson said cylinder .[.and.]. positioned to engage .[.the flap.]. .Iadd.theflange .Iaddend.of .[.the.]. .Iadd.said .Iaddend.first valve when said.Iadd.valve .Iaddend.body is in said second position, and secondprojection means which engages the flange of said second valve when said.Iadd.valve .Iaddend.body is in said first position.Iadd., furtherwherein said flanges are circular.Iaddend..
 6. A valve assembly for asyringe having an interacting piston and cylinder, with the cylinderterminating at one end with a mounting to receive a syringe needle, saidpiston and cylinder co-operating to define a variable volume workingchamber which receives a liquid to be injected by the syringe, saidvalve assembly being adapted to be located within said chamber so as todivide said chamber into a first sub-chamber located adjacent the needlemounting.[.,.]. and a second sub-chamber located adjacent the piston,said valve assembly .].including;.]. .Iadd.comprising the followingcomponents: .Iaddend.a valve sleeve to be sealingly received within saidcylinder so as to be coaxial with respect thereto, said sleeve having aninternal peripheral surface; a movable valve member received within saidsleeve and sealingly co-operating therewith so that in use of thesyringe the valve member selectively controls the direction of flow ofliquid within the syringe, said valve member having a pair of axiallyspaced .[.annular.]. .Iadd.circular .Iaddend.sealing surfaces whichsealingly engage said sleeve, and which are resiliently deformed; afirst set of sleeve projections extending inwardly of said sleeve toengage a first one of said sealing surfaces.[.;.]..Iadd., and .Iaddend.a second set of sleeve projections extending inwardly of said sleeve toengage the other sealing surface, said second set of sleeve projectionsbeing spaced longitudinally of said first set of sleeve projections.[.;and.]..Iadd., .Iaddend. wherein said valve member is longitudinallymovable between a first .[.portion.]. .Iadd.position .Iaddend.whereinthe first .[.annular.].sealing surface is engaged with .[.the.]..Iadd.said .Iaddend.first set of sleeve projections so as to be deformedand deflected from said sleeve so that liquid may pass thereby, and theother sealing surface is in sealing contact with said sleeve andinhibits .[.the direction of.]. fluid flow in a first direction, and asecond position wherein .[.said.]. .Iadd.the .Iaddend.second sealingsurface is engaged with said second set of sleeve projections so thatliquid may pass thereby, and said first sealing surface is sealinglyengaged with said sleeve to inhibit fluid flow in a second direction.[.,which is.]. opposite to said first direction.
 7. A single use syringe.[.having.]. .Iadd.comprising .Iaddend.an interacting piston andcylinder, with the cylinder terminating at one end with a mounting toreceive a syringe needle, said piston and cylinder cooperating to definea variable volume working chamber which receives a liquid to be injectedby the syringe, and .[.the.]. .Iadd.a .Iaddend.valve assembly .[.ofclaim 6.]., which valve assembly is located within said chamber so as todivide said chamber into .[.said.]. .Iadd.a .Iaddend.first sub-chamberand .[.said.]. .Iadd.a .Iaddend.second sub-chamber.Iadd., and whichvalve assembly includes the following components:a valve sleeve to besealingly received within said cylinder so as to be coaxial with respectthereto, said sleeve having an internal peripheral surface; a movablevalve member received within said sleeve and sealingly co-operatingtherewith so that in use of the syringe the valve member selectivelycontrols the direction of flow of liquid within the syringe, said valvemember having a pair of axially spaced circular sealing surfaces whichsealingly engage said sleeve, and which are resiliently deformed; afirst set of sleeve projections extending inwardly of said sleeve toengage a first one of said sealing surfaces, and a second set of sleeveprojections extending inwardly of said sleeve to engage the othersealing surface, said second set of sleeve projections being spacedlongitudinally of said first set of sleeve projections, wherein saidvalve member is longitudinally movable between a first position whereinthe first sealing surface is engaged with said first set of sleeveprojections so as to be deformed and deflected from said sleeve so thatliquid may pass thereby, and the other sealing surface is in sealingcontact with said sleeve and inhibits fluid flow in a first direction,and a second position wherein the second sealing surface is engaged withsaid second set of sleeve projections so that liquid may pass thereby,and said first sealing surface is sealingly engaged with said sleeve toinhibit fluid flow in a second direction opposite to said firstdirection. .Iaddend. .Iadd.8. A valve for a single use syringe having aninteracting piston and cylinder and a syringe needle, said valvecomprising: duct means providing a passage through which liquid to beinjected must pass to be delivered to said needle; a movable valve bodylocated in said duct means and dividing said passage into a firstsub-chamber and a second sub-chamber with, said first sub-chamber to belocated closer to said needle than said second sub-chamber, said valvebody being movable longitudinally of said duct means between a firstposition and a second position under the influence of pressure appliedthereto through said liquid, wherein said valve body includes 1) a firstvalve means sealingly co-operating with said duct means, which, whensaid valve body is in said first position, permits flow from said firstsub-chamber to said second sub-chamber and prevents flow from saidsecond sub-chamber to said first sub-chamber, but which, when said valvebody is in said second position, permits flow from said secondsub-chamber to said first sub-chamber, and 2) a second valve meanswhich, when said valve body is in said first position, permits flow fromsaid first sub-chamber to said second sub-chamber, but which, when saidbody is in said second position, prevents flow from said firstsub-chamber to said second sub-chamber, and means to prevent movement ofsaid valve body from said second position to said first position..Iaddend. .Iadd.9. The valve of claim 8, wherein said second position ofsaid valve body is intended to be closer to said needle than said firstposition of said valve body. .Iaddend. .Iadd.10. The valve of claim 8 or9, wherein said first and second valve means include valve flapsattached to a central portion of said valve body, and said duct meanshas recesses selectively sealingly co-operating with said valve flaps..Iaddend. .Iadd.11. The valve of claim 9, wherein said valve body isformed of resilient material, and each of said valve means includes aresilient circular flange, and said each of said valve means furtherincludes projection means on an internal peripheral surface of a sleevepositioned to engage said first valve means when said valve body is insaid second position and to engage said second valve means when saidvalve body is in said first position. .Iaddend. .Iadd.12. The valve ofclaim 11, wherein said projection means includes 1) first projectionmeans to engage said first valve means, positioned to deflect said firstvalve means from sealing engagement with said duct means when said valvebody is in said second position, and 2) second projection means toengage said second valve means to move it from sealing contact with saidduct means when said valve body is in said first position. .Iaddend..Iadd.13. The valve of claim 9, whereinsaid piston and cylinder providea primary chamber; said valve is adapted to be located within saidprimary chamber so as to divide said primary chamber into said firstsub-chamber, which is located adjacent the needle mounting, and saidsecond sub-chamber, which is located adjacent said piston, and saidvalve is sealingly received within said cylinder so as to be coaxialwith respect thereto. .Iaddend. .Iadd.14. A single use syringecomprising the following components: (I) an inter-acting piston andcylinder defining a variable volume primary chamber within which aliquid to be injected is drawn; (II) a needle mounting at one end ofsaid cylinder to receive a needle; (III) a passage extending throughsaid mounting enabling liquid communication between said cylinder andneedle; (IV) a piston rod attached to said piston and operable by a userto cause movement of said piston to vary the volume of said primarychamber, and (V) a valve, through which said liquid must pass in flowingbetween said needle and primary chamber, which valve includes (A) ductmeans providing a passage through which liquid to be injected must passto be delivered to said needle; (B) a movable valve body located in saidduct means and dividing said passage into a first sub-chamber and asecond sub-chamber, with said first sub-chamber to be located closer tosaid needle than said second sub-chamber, said valve body being movablelongitudinally of said duct means between a first position and a secondposition under the influence of pressure applied thereto through saidliquid, wherein said valve body includes 1) a first valve meanssealingly co-operating with said duct means, which, when said valve bodyis in said first position, permits flow from said first sub-chamber tosaid second sub-chamber and prevents flow from said second sub-chamberto said first sub-chamber, but which, when said valve body is in saidsecond position, permits flow from said second sub-chamber to said firstsub-chamber, and 2) a second valve means which, when said valve body isin said first position, permits flow from said first sub-chamber to saidsecond sub-chamber, but which, when said body is in said secondposition, prevents flow from said first sub-chamber to said secondsub-chamber, and (C) means to prevent movement of said valve body fromsaid second position to said first position, wherein said secondposition of said valve body is intended to be closer to said needle thansaid first position of said valve body. .Iaddend. .Iadd.15. The syringeof claim 14, wherein said valve body is located within said primarychamber between said mounting and piston, and said cylinder providessaid passage. .Iaddend. .Iadd.16. The syringe of claim 14, wherein saidvalve is located in said needle mounting. .Iaddend. .Iadd.7. The valveof claim 8, wherein said second position is intended to be closer to theneedle than said first position. .Iaddend. .Iadd.18. The valve of claim17, characterized in that the flow from said first sub-chamber to saidsecond sub-chamber can charge the syringe with liquid, while the flowfrom said second sub-chamber to said first sub-chamber provides forinjection of the liquid from the syringe. .Iaddend. .Iadd.19. The valveof claim 18, characterized by further including annular seal meanssurrounding a portion of said passage and wherein said valve bodyengages one side of said seal means in said first position before beingmoved longitudinally, under the influence of said pressure, relativesaid seal means to said second position, at which said valve bodyengages the other side of said seal means to prevent flow from saidfirst sub-chamber to said second sub-chamber. .Iaddend..Iadd.20. Thevalve of claim 19, wherein said first and second valve means are leadingand trailing portions of said valve body with respect to movement ofsaid valve body in the direction of movement between said first positionand said second position. .Iaddend. .Iadd.21. The valve of claim 20,wherein said means to prevent movement of said valve body from saidsecond position to said first position is in the configuration of saidvalve body and said seal means. .Iaddend. .Iadd.22. The valve of claim21, wherein said seal means provides a valve opening through which saidvalve body passes. .Iaddend. .Iadd.23. The valve of claim 22, whereinresilient deformation permits movement of said valve body through saidseal means. .Iaddend. .Iadd.24. The valve of claim 23, wherein saidfirst and second valve means are resilient circular end walls of saidvalve body, which valve body includes a longitudinal stem joining theend walls. .Iaddend. .Iadd.25. The valve of claim 24, wherein saidsecond valve means co-operates with said seal means to prevent flow fromsaid first sub-chamber to said second sub-chamber when said valve bodyis in its second position, and said first valve means co-operates withsaid seal means to prevent flow from said second sub-chamber to saidfirst sub-chamber when said valve body is in its first position..Iaddend. .Iadd.26. The valve of claim 25, wherein said second valvemeans is resiliently deformable so as to pass through said valve openingwhen said valve body is moved from the first position to said secondposition. .Iaddend. .Iadd.27. The valve of claim 22, wherein said firstand second valve means are circular end walls. .Iaddend. .Iadd.28. Thevalve of claim 19, which further includes annular seal means surroundinga portion of said passage, and projection means to engage said firstvalve means when said valve body is in said second position, wherein thevalve means are valve flanges of circular configuration, and said valvebody extends through said seal means when said valve body is in eithersaid first or said second position. .Iaddend. .Iadd.29. The valve ofclaim 8 or 18, wherein said first and second valve means are leading andtrailing portions of said valve body with respect to movement of thevalve body in the direction of movement between said first position andsaid second position.